When I interviewed Ash Grunwald for The Brag at the start of this year, he was in a reflective mood. After a hectic 2012 that saw the release of his sixth studio album, plus tours and EPs from no fewer than four side projects, he finally had some free time to reflect on the tenth anniversary of his solo career.

All the different side projects were part of a conscious effort by Grunwald to spread his wings and expand his horizons, but when we spoke he seemed ready to put a stop to the scattershot approach. He was ready to get back to basics.

“You keep playing, and pushing it, and proving to yourself and your audience that you can do this, that and the other thing,” he said at the time, “And then after a while you start to think about what your unique thing is that you bring to the table, and then you start to distil it a little bit back to that essence. And then you can go off again.”

But when I spoke to him again a couple of weeks ago and reminded him of his earlier intentions, Grunwald laughed. For quite a long time. Because instead of finding his essential self, Grunwald is about to release Gargantua: the loudest, heaviest, nastiest album of his career.

To be fair to Grunwald, this album was the furthest thing from his mind when he asked Andy Strachan (drums) and Scott Owen (bass) – two-thirds of The Living End and arguably the greatest rhythm section in the country – to do a little tour together. But after they played a couple of raucous, rapturously-received gigs Grunwald started to think maybe they could record a couple of tracks together.

They recorded a cover of Gnarls Barkley’s ‘Crazy’ that got some significant airplay on commercial radio – a first for Grunwald, who has never been straightforward enough for the format – and even led to the trio being invited on to Triple M to play the track live in the studio. That night Grunwald, Strachan and Owen went to see pantomime rock gods Tenacious D, and inspired by the big, dumb fun of it all headed straight to the studio. Grunwald still seems to have a bit of whiplash at the speed of it all.

“I have never, ever in my life done anything this quickly,” says Grunwald. “I’ve never even heard of anything being done this quickly. I’ve never heard of people booking a tour, and then recording an album just before the tour, and then turning it into an album tour, which is pretty much what’s happening. So it’s all very strange, and very fun.”

On paper, Gargantua doesn’t seem like much of anything. Some mates got together to bash out a couple of new tracks, a couple of covers and new recordings of old material. But what makes it compelling is how the tracks are played, the ways in which each individual’s consummate musicianship comes to the fore, and the way partnerships form between different members of the trio at different times.

“One thing Scotty mentioned was that hearing how they play on my stuff, and what they do to it, you can hear that it’s not just Scotty as an individual and Andy as an individual – you can hear them putting some Living End into the music,” Grunwald begins. “And that’s interesting, because as a frontman it’s great to have a great bass player and a great drummer, and they make it better because they’re better. But you don’t realise how they influence the songs. And that’s the dynamic of a three-piece – they really play a huge role in what they do. And Andy’s just such an exciting drummer.”

Gargantua is an albumwith no shortage of talking points, particularly when it comes to Grunwald’s influences – the three covers on the album are from wildly different sources (Gnarls Barkley, Howlin’ Wolf, and legendary Australian blues band Chain), and Grunwald loves the guitars and the aggression of Rage Against the Machine (“I really chalk them up as one of my non-blues influences,” he says, laughing. “But it’s really that one song [‘Killing In The Name’]!”) But undoubtedly the biggest influence on the album is the slow destruction of the Australian landscape by coal-seam mining, particularly fracking.

Grunwald has seen first-hand the extraordinary damage the industry is doing to our country – he filmed the Condamine River bubbling with methane gas, and saw the land being destroyed to build highways for CSG trucks to drive on. And so when the track ‘The Last Stand’ was knocked back by the producers of the Schwarzenegger film he wrote it for, he had some lyrics just raring to go.

“The more direct lyrics in there are from interviews with people in that area,” Grunwald explains. “I didn’t know I would write a song about it until I got up there, but I didn’t realise how bad it was up there.

“I’m really keen that the gig not turn into a rally. I’m very passionate about it, but I just want to let people know as part of the gig, and then move on, and have a party at the gig. They didn’t come for a political rally, but I do think it’s very important that people know about it. And I think the way I’m going to do it at the show is to just ask everyone to go to YouTube and type in ‘CSG’. I think that’s all that needs to be done, and they’ll find out for themselves. It’s all there.”